Space telerobot systems may present a master control site that is many, many, miles away from the remote site. Teleoperator mode of control with a back-driveable hand controller implies communication-intensive feedback to the master site. Moreover, both site locations must have essentially real-time information of what has transpired at the other site location. In a teleoperator mode, software such as a display readout/visual display is essential and further complicates the communication requirements. Commands on a hand-held grip at the master site must perform intricate and precise movement and manipulation of a robot's joints and it's end effector at the remote site.
Communication by data transmission links is obviously mandatory, and simple, yet efficient ways of handling large amounts of data is essential for an efficient system performance. Computer control at each site for sensing, encoding, transmitting/receiving, mathematically translating, viewing and responding to such robotic control information involves processor activities that are computational intensive at each site. Such computer control is eminently the most reasonable approach when the manual master controller is not a kinematic and dynamic duplicate of the robot arm, but instead takes the form of a generalized force-reflecting hand controller which is interfaceable to any robot. Such a master controller is exemplified by an experimental device that has been developed at the Jet Propulsion Laboratory (JPL). In that experimental device, the kinematic and dynamic relations between master and robot arms are established through mathematical transformations embodied in computer programs in the control station. See A. K. Bejczy and J. K. Salisbury, Jr., Kinesthetic Coupling Between Operator and Remote Manipulator, Computers in Mechanical Engineering, Vol. 1, No. 1, July 1983, pp. 48-60. Such transformations per se are well known and do not form part of this invention.
The master location will often include a hand controller that is capable of movement in six degrees-of-freedom ("d.o.f."), which hand controller preferably is back-driveable in those degrees in order to supply a "feel" of what is taking place at the remote site. Control action, whether manual or computer-driven, involves many well known control modes including pure position, pure rate, hybrid position and rate, and/or a hybrid position and force control mode.
All of the aforementioned modes may advantageously benefit from software control programs, and each mode of control may require the hand controller to be software restricted to one or a limited number of the six possible degrees-of-freedom that are available. These numerous and inter-connected system requirements present a complex telemanipulation problem that is further complicated by the communication difficulties encountered by the great distances between the master and remote sites.
Future space operations relating to space station, satellite and space platform servicing, maintenance and assembly call for an increased application of telerobots. The term telerobot denotes a mobile and manipulative machine which can be controlled via (automatic/autonomous) modes of control. A typical machine of this category is illustrated in FIG. 1 of an article co-authored by the inventor hereto entitled "Universal Computer Control System (UCCS) for Space Telerobots", IEEE Proceeding of the International Conference On Robotics, 1987 which article forms the basis for the parent application of this continuation-in-part application. The typical machine of FIG. 1 of the above-identified article has redundant arms, multi d.o.f. end effectors, and several TV cameras and light sources on independent multi d.o.f. platforms. The number of actuators or motors required to drive the articulated elements of a typical telerobot machine of this category can be thirty or more. The large number of computer controlled motors in space telerobot systems, and the inherent requirement of their computer control coordination, was the motivation behind the JPL research and development of a Universal Computer Control System ("UCCS") which includes a Universal Motor Control ("UMC") for all of the motor elements of a space telerobot system as described and claimed in the parent application.
The UCCS and UMC portion of the parent application is not repeated in detail in this application but is highly useful for digital control over and digital feedback from the many joint motors involved in the master-slave interrupt-driven synchronized system of this application. In addition, it should be noted that the invention of that parent application involves a motor control system which is capable of fulfilling the diverse overall requirements faced in the novel telemanipulator system disclosed herein although other motor control systems would be applicable as well. Most of the lower-level details of that parent application will not be repeated herein and those details as well as some of the general system aspects will, instead, be incorporated by reference as is set forth more explicitly hereinafter.
Some of the prior art relevant to consideration of the novelty of this and the parent application will now be discussed. Robotic control articles and prior art patents of the parent application are simply listed herein and reference to the parent may be made for more detailed consideration of this prior art. Two published systems, of general interest, are described in Control of Remote Manipulators, Handbook of Industrial Robotics, Wiley, New York, Chapter 17, pp. 320-333, 1985 and S. Lee, G. Bekey, and A. K. Bejczy, Computer Control of Space-Borne Teleoperators with Sensory Feedback, Proceedings of the IEEE International Conference on Robotics and Automation, St. Louis, Mo., Mar. 25-28, 1985, pp. 205-214.
The patents resulting from a search in the parent application include the following:
______________________________________ Inaba 4,475,160 Hutchins et al. 4,488,241 Niedermayr 4,611,296 Japan 60-230206 Japan 60-214007 Japan 57-113118 Japan 60-209802 Eder 4,099,107 Lee 4,300,080 Iwata 4,621,331 Sugimoto et al. 4,621,332 Pollard et al. 4,362,978 Takahashi et al. 4,639,652 ______________________________________
A prior art search was conducted relative to this invention and the following patents were noted.
Murata U.S. Pat. No. 4,633,385 PA0 Mori U.S. Pat. No. 4,608,525 PA0 Engelberger U.S. Pat. Nos. 4,260,941 and 4,275,986 PA0 Devol U.S. Pat. No. 3,890,552 PA0 Takeda U.S. Pat. No. 4,503,507 PA0 Rohrle U.S. Pat. No. 4,684,862
None of these references teach or suggest the invention as herein described or claimed. For example, none of the references teach or suggest the use of sensory data at the robot site which is transmitted over a balanced-load communication channel to backdrive "feel" actuators on the hand controller of the master arm. These features involve computational intense problems that are solved by a novel synchronism and software/hardware configuration that is first presented in this disclosure.